42 lines
1.3 KiB
Java
42 lines
1.3 KiB
Java
// patterns/trash/GroupingBy.java
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// (c)2021 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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// {java patterns.trash.GroupingBy}
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package patterns.trash;
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import java.util.*;
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import java.util.stream.*;
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public class GroupingBy {
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public static void main(String[] args) {
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List<Trash> bin = new ArrayList<>();
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ParseTrash.fillBin("trash", bin);
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Map<Class, List<Trash>> m =
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bin.stream().collect(
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Collectors.groupingBy(Object::getClass));
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ClassToListOfTrashMap.show(m);
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}
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}
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/* Output:
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Loading patterns.trash.Cardboard
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Loading patterns.trash.Paper
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Loading patterns.trash.Aluminum
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Loading patterns.trash.Glass
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Glass weight: 5.40 * price: 0.23 = 1.24
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Glass weight: 4.30 * price: 0.23 = 0.99
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Glass weight: 3.60 * price: 0.23 = 0.83
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Total Glass value = 3.06
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Paper weight: 8.00 * price: 0.10 = 0.80
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Paper weight: 6.60 * price: 0.10 = 0.66
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Paper weight: 9.10 * price: 0.10 = 0.91
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Total Paper value = 2.37
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Cardboard weight: 4.40 * price: 0.11 = 0.48
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Cardboard weight: 2.20 * price: 0.11 = 0.24
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Cardboard weight: 1.20 * price: 0.11 = 0.13
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Total Cardboard value = 0.86
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Aluminum weight: 1.80 * price: 1.67 = 3.01
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Aluminum weight: 3.40 * price: 1.67 = 5.68
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Aluminum weight: 2.70 * price: 1.67 = 4.51
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Total Aluminum value = 13.19
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*/
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